JP2019081851A - Acrylic resin composition - Google Patents

Abstract

To provide an acrylic resin composition which is excellent in transparency, and scratch resistance (initial and heat heatproof).SOLUTION: An acrylic resin composition contains 0.5-5 pts.mass of component (B) to 100 pts.mass of component (A). (A) acrylic resin. (B) polyethylene glycol in which a molecular weight at a refractive index intensity maximum point in chromatogram obtained using a differential refractive index meter by gel permeation chromatography is 5,001-25,000, and when a peak area from an elution start point to an elution time corresponding to the refractive index intensity maximum point is represented by S, and a peak area from the elution time corresponding to the refractive index intensity maximum point to an elution end point is represented by S, S/Sis 1.3 to 3.0.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an acrylic resin composition capable of producing a molded article excellent in transparency and scratch resistance (initial and after heat resistance).

  Acrylic resin is widely used in automotive glazing, lamp lenses, and roof parts of terraces and garages because it is a highly transparent resin. However, since acrylic resin has a surface hardness lower than that of metal and glass, it has the disadvantage that the surface is easily scratched if it is exposed to heat and is subjected to friction due to stepping stones or flying sand.

  As a method for solving the scratch resistance of the acrylic resin, a hard coat on the surface of a molded article made of an acrylic resin or an insert molding of a hard-coated film has been proposed. However, it has the disadvantages that it is difficult to coat complex shaped products, the coating is expensive, and the process is complicated.

  On the other hand, for example, in Patent Document 1, an acrylic resin and an ethylene / α-olefin copolymer rubber, or an ethylene / α-olefin / non-conjugated diene copolymer rubber, an ethylene / vinyl copolymer, and a fatty acid A method has been proposed to blend a surface property modifier composition comprising an amide and a graft copolymer.

JP, 2015-131948, A

  However, in the formulation described in Patent Document 1, there is a problem that the transparency is impaired, and there is a problem that the volatility of fatty acid amide which is an active component of scratch resistance expression is high, and the scratch resistance decreases after heat resistance.

  An object of the present invention is to provide an acrylic resin composition capable of producing a molded article excellent in transparency and scratch resistance (initial and after heat resistance).

The present invention relates to an acrylic resin composition containing 0.5 to 5 parts by mass of the following component (B) with respect to 100 parts by mass of the following component (A).

(A) Acrylic resin (B) Polyethylene glycol having a molecular weight of 5,001 to 25,000 at the maximum refractive index intensity in the chromatogram obtained by gel permeation chromatography using a differential refractometer The peak area from the elution start point to the elution time point corresponding to the refractive index intensity maximum point is S _1, and the peak area from the elution time point to the elution end point corresponding to the refractive index intensity maximum point is S _{2 when, S} 2 / S ₁ is 1.2 to 3.0.

  ADVANTAGE OF THE INVENTION According to this invention, the acrylic resin composition which can manufacture the molded article excellent in transparency and scratch resistance (initially and after heat resistance), especially a heat resistant acrylic resin composition can be provided.

FIG. 1 is a model chromatogram diagram for explaining peak areas S ₁ and S ₂ defined in the present invention.

Hereinafter, the present invention will be described in more detail.
<(A) Acrylic resin>
As acrylic resin, poly methyl methacrylate, poly ethyl methacrylate, poly propyl methacrylate, poly butyl methacrylate, poly poly methyl acrylate, poly ethyl acrylate, methyl methacrylate-methyl acrylate copolymer, methyl methacrylate -Alkyl ester compounds such as methyl, ethyl, propyl and butyl of (meth) acrylic acid such as ethyl methacrylate copolymer, methyl methacrylate-butyl methacrylate copolymer and methyl methacrylate-ethyl acrylate copolymer Homopolymers or copolymers may be mentioned. These acrylic resins may be used alone or in combination of two or more. There is no particular limitation on the method for producing the same, and known suspension polymerization method, emulsion polymerization method, bulk polymerization method may be used. Etc. are used.

  The weight average molecular weight of the acrylic resin in the present invention is preferably 50,000 to 500,000.

<(B) polyethylene glycol>
Polyethylene glycol (B) has a molecular weight of 5,001 to 25,000 at a refractive index maximum point in a chromatogram obtained by gel permeation chromatography using a differential refractometer. Even if the peak area ratio S ₂ / S ₁ described later is 1.3 to 3.0, scratch resistance (after heat resistance) decreases if the molecular weight of polyethylene glycol is less than 5,001. From such a viewpoint, the molecular weight of polyethylene glycol is 5,001 or more, preferably 5,100 or more, more preferably 5,500 or more, and still more preferably 8,000 or more. In addition, it is difficult to produce polyethylene glycol having a molecular weight of more than 25,000, and even if the peak area ratio S ₂ / S ₁ is 1.3 to 3.0, the molecular weight is more than 25,000. Since the transparency tends to decrease, it is 25,000 or less, preferably 23,000 or less.

The polyethylene glycol (B) further defines a peak area from the elution start point to the elution time point corresponding to the refractive index intensity maximum point as S _1, and the peak area from the elution time point to the elution end point corresponding to the refractive index intensity maximum point the when the _{S 2, S 2} / _{S 1} is 1.3 to 3.0.

Even if the molecular weight of the polyethylene glycol (B) is 5,001 to 25,000, if the peak area ratio S ₂ / S ₁ described later is greater than 3.0 (the proportion of polyethylene glycol having a molecular weight of less than 5,001) High), the scratch resistance (after heat resistance) decreases. From this viewpoint, S ₂ / S ₁ is 3.0 or less, preferably 2.5 or less. When the peak area ratio S ₂ / S ₁ is smaller than 1.3 (when the proportion of polyethylene glycol having a molecular weight of more than 25,000 is high), the scratch resistance (initial) is reduced.

This requirement is further described below.
The peak area ratio (S ₂ / S ₁ ) is defined in gel permeation chromatography (GPC) by the chromatogram obtained using a differential refractometer. The chromatogram is a graph showing the relationship between the refractive index intensity and the elution time.

  Here, FIG. 1 is a model diagram of a chromatogram obtained by gel permeation chromatography of polyethylene glycol, the horizontal axis indicates the elution time, and the vertical axis indicates the refractive index intensity obtained using the differential refractometer. .

  When a sample solution is injected into a gel permeation chromatograph and developed, elution starts from the molecule with the highest molecular weight, and the elution curve rises as the refractive index intensity increases. Thereafter, the elution curve descends after passing the refractive index intensity maximum point K at which the refractive index intensity reaches its maximum.

  Polyethylene glycol (B) has a single peak, which is usually one refractive index maximum point in the chromatogram in gel permeation chromatography. Under the present circumstances, the peak resulting from the developing solvent etc. which were used for gel permeation chromatography, and the pseudo peak by the fluctuation of the baseline resulting from the used column and apparatus are remove | excluded.

Here, the peak area from the elution start point O to the elution time point C corresponding to the refractive index intensity maximum point K is taken as S ₁ . The elution time point C is at the intersection of a perpendicular P drawn from the refractive index intensity maximum point K to the baseline B and the baseline B. Then, the peak area from the elution time C until dissolution end point E and S _2. Peak area S ₁ corresponds to the amount of components of relatively high molecular weight side, the peak area S ₂ corresponds to the amount of components of relatively low molecular weight side. And that S ₂ / S ₁ is 1.2 to 3.0 means that the component on the low molecular weight side is more to a certain extent than the component on the high molecular weight side, and this molecular weight balance is an acrylic resin It contributes to the scratch resistance (initial and after heat resistance) of the composition.

In the present invention, gel permeation chromatography (GPC) for determining the peak area ratio (S ₂ / S ₁ ) uses TOSOH HLC-8320 GPC as a GPC system and two TOSOH TSKgel Super Multipore HZ-M as a column. And one TOSOH TSKgel Super H-RC. Then, the column temperature is set to 40 ° C., the reference substance is polystyrene, and tetrahydrofuran is used as a developing solvent. The developing solvent was flowed at a flow rate of 1 ml / min, and 0.1 ml of a sample solution having a sample concentration of 0.1% by weight was injected. Molecular weight is a weight average molecular weight calculated | required based on the chromatogram represented with the refractive index intensity | strength and elution time which were obtained using EcoSEC-Work Station GPC calculation program.

(Ratio of each ingredient)
In the composition of the present invention, when the content of the component (A) is 100 parts by mass, the content of polyethylene glycol of the component (B) is 0.5 to 5 parts by mass. Thereby, the transparency of the acrylic resin composition is maintained, and scratch resistance (initial and after heat resistance) is improved. If the content of polyethylene glycol is less than 0.5 parts by mass, scratch resistance (initial and after heat resistance) tends to decrease, and therefore, 0.5 parts by mass or more, but 1 part by mass or more Is more preferred. When the content of the polyethylene glycol exceeds 5 parts by mass, the transparency tends to decrease, so the amount is 5 parts by mass or less, and more preferably 4 parts by mass or less.

<Other additives>
To the acrylic resin composition of the present invention, other additives such as rubber, plasticizer, softener, antioxidant, processing aid, flame retardant, ultraviolet light absorber, coloring agent and the like are used insofar as the effects of the present invention are not impaired. Agents can be added.

  The acrylic resin composition of the present invention can be produced by melt-kneading (A) acrylic resin and (B) polyethylene glycol, and the kneading temperature is 200 to 300 ° C., preferably 220 to 280 ° C. Preferably it may carry out at 230-260 ° C.

  For kneading of (A) acrylic resin and (B) polyethylene glycol, a continuous extruder such as a single-screw extruder, a twin-screw extruder, or a twin-rotor extruder can be used. The obtained acrylic resin composition can be molded into a predetermined shape by a known molding method such as an extrusion molding method, an injection molding method, a blow molding method, or a compression molding method.

  The acrylic resin composition of the present invention is excellent in transparency and scratch resistance (initial and after heat resistance). Therefore, it can be used as a material of optical parts such as automobiles, electric / electronic devices, building materials, and designed parts.

Hereinafter, specific examples of the present invention will be described.
<Acrylic resin composition>
The acrylic resin composition was obtained by dry blending each component with each composition shown in Table 1 and Table 2 and kneading and granulating with a twin-screw extruder at a set temperature of 230 ° C. The obtained acrylic resin composition was injection molded with an injection molding machine at a cylinder temperature of 230 ° C. and a mold temperature of 80 ° C., and the transparency and scratch resistance (initial and after heat resistance) were evaluated.

The evaluation method of each performance is as follows.
Transparency
The haze (%) of the test piece (80 mm × 55 mm × t2 mm) was measured with NDH 5000 manufactured by Nippon Denshoku Kogyo.

<Scratch resistance (initial)>
Test pieces (80 mm × 55 mm × t2 mm) were scratched in a grid by 30 squares each at 1 mm intervals using a scratch tester 430P made by ERICHSEN with a load of 8 N, a pin shape of 1 mmφ, and a scratching speed of 1,000 mm / min. Attached. The haze before and after the scratch of the test piece was measured with NDH 5000 manufactured by Nippon Denshoku Kogyo Co., Ltd., and the difference (ΔHaze) was calculated.

<Scratch resistance (after heat resistance)>
After leaving the test piece (80 mm × 55 mm × t2 mm) in a gear oven set at 80 ° C. for 504 hours, using a scratch tester 430P made by ERICHSEN, a load of 8 N, a pin shape of 1 mmφ, and a scratching speed of 1,000 mm / min Then, 30 horizontal and 30 vertical and horizontal lines were scratched at intervals of 1 mm. The haze before and after the scratch of the test piece was measured with NDH 5000 manufactured by Nippon Denshoku Kogyo Co., Ltd., and the difference (ΔHaze) was calculated.

  As is clear from the results in Table 1, Examples 1 to 6 were all excellent in transparency and scratch resistance (initial and after heat resistance).

On the other hand, in Comparative Examples 1 to 7, their performance balance was insufficient.
Specifically, Comparative Example 1 was inferior in scratch resistance (after heat resistance) because the molecular weight of polyethylene glycol was too small.

Comparative Example 2 and Comparative Example 4 were inferior in scratch resistance (initial) because the peak area ratio S ₂ / S ₁ in gel permeation chromatography of polyethylene glycol was too small.
Comparative Example 3 and Comparative Example 5 were inferior in scratch resistance (after heat resistance) because the peak area ratio S ₂ / S ₁ in gel permeation chromatography of polyethylene glycol was too large.

Comparative Example 6 was inferior in scratch resistance (initial and after heat resistance) because the blending amount of polyethylene glycol was too small.
Comparative Example 7 was inferior in transparency because the blending amount of polyethylene glycol was excessive.

Hereinafter, the suitable compounding example of the acrylic resin composition of this invention is demonstrated. In Formulation Examples 1 to 3, Acrypet VH 001 manufactured by Mitsubishi Rayon Co., Ltd. was used as the acrylic resin, and polyethylene glycol having a molecular weight of 23,000 and S ₂ / S ₁ of 2.2 was used.

Formulation Example 1
Acrylic resin (A): 100 parts by mass Polyethylene glycol (B): 3 parts by mass Pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate]:
0.1 parts by mass

Formulation Example 2
Acrylic resin (A): 100 parts by mass Polyethylene glycol (B): 3 parts by mass 2- [4,6-diphenyl-1,3,6-triazin-2-yl] -5- (hexyloxy) phenol:
0.2 parts by mass

Formulation Example 3
Acrylic resin (A): 100 parts by mass Polyethylene glycol (B): 3 parts by mass 2,2′-methylenebis [6- (benzotriazol-2-yl) -4-tert-octylphenol]:
0.2 parts by mass

  The acrylic resin compositions obtained in Formulation Examples 1 to 3 were all excellent in transparency and scratch resistance (initial and after heat resistance).

Claims (1)

An acrylic resin composition comprising 0.5 to 5 parts by mass of the following component (B) with respect to 100 parts by mass of the following component (A).

(A) Acrylic resin

(B) Polyethylene glycol which is obtained by gel permeation chromatography using a differential refractometer and has a molecular weight of 5,001 to 25,000 at the refractive index maximum point, and an elution starting point wherein the peak area up to the elution time corresponding to the refractive index intensity maxima and S _1, when the peak area up to the elution end point from the elution time corresponding to the refractive index intensity maxima was S ₂ from, S ₂ / S ₁ is 1.3 to 3.0.

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